Co-secretion of growth hormone and prolactin defines a high-risk acromegaly phenotype.

BACKGROUND

Data on GH and prolactin (PRL) co-secreting pituitary neuroendocrine tumors (GH/PRL-PitNETs), a subtype of acromegaly, remain limited. In particular, comparative analyses of clinical outcomes, including remission rates, between GH/PRL-PitNETs and GH-secreting pituitary neuroendocrine tumors (GH-PitNETs) are scarce.

OBJECTIVE

This study aimed to characterize and compare the clinical course and remission outcomes of GH/PRL-PitNETs and GH-PitNETs.

METHODS

We retrospectively analyzed 188 patients with acromegaly who underwent surgery between 2018 and 2024. GH/PRL-PitNETs (n = 46) were compared with GH-PitNETs (n = 142) in terms of their clinical, biochemical, and radiological features. Kaplan-Meier analysis was used to assess differences in biochemical remission between the groups, after which Cox proportional hazards modeling-including a time-dependent treatment variable-was used to identify covariates independently associated with remission.

RESULTS

GH/PRL-PitNETs were significantly larger and more invasive than GH-PitNETs. The surgical remission rate was lower in the GH/PRL-PitNET group (P = .023). In multivariable Cox analysis, tumor size and cavernous sinus invasion independently predicted inferior outcome in biochemical remission. GH-PitNETs showed a higher incidence of medical comorbidities such as hypertension and thyroid carcinoma.

CONCLUSION

GH/PRL-PitNETs demonstrated greater tumor burden and more pronounced structural invasiveness, resulting in a significantly lower likelihood of endocrinological remission.